He is the author of GNU Modula-2 and the groff html device driver grohtml. His research interests also include performance of microkernels and compiler design. He obtained a Bsc(Hons) in Computer Science from the University of Reading in 1985 and a PhD in Computer Science from the University of Reading in 1989. He then worked for Meiko Scientific before joining the University of Glamorgan (now Southwales) in 1994. He is the author of PGE (Predictive Game Engine).